The Brazilian center-back will stay for another 12 months at the Emirates Stadium, confirmed Arsenal on Wednesday morning.
Especially in the 3-0 loss to Manchester City last week when faulting for two goals before being sent off, the news comes on the back of some questionable Luiz displays.
Petit feels the decision reflects the direction his former club is heading, he won the Premier League and FA Cup at Arsenal playing under Arsene Wenger.
“For about three years, David Luiz hasn’t been a good footballer, but I’m not surprised that he was awarded a new contract at Arsenal because I was very disappointed with the activity of the club on the transfer market,” he told.
“I was particularly upset about the defenders. We all know that one of the major weaknesses of Arsenal is their defense and nothing has changed.”